In the supervisory control of industrial plants there is continual and generally increasing requirement for information about plant equipment, current and historic process data, trends, etc. This information is typically provided by the control system and usually in the form of one or more distributed control systems (DCS) and/or supervisory control and data acquisition (SCADA) systems. With the increases in computing power and advances in communication and computerized measurement there is an increasing amount of data available for the operators.
The information is often presented to the operators through a display screen showing process graphics that presents process data (measurements, values), tag identifiers, equipment ID, alarm status, connections between plant equipment, etc. As more and more data is presented to the operators, the visual user interfaces each often hold very much information.
The task of finding the relevant technical information for a given technical subject or condition in a large information space is further complicated by the fact that in many situations the operator often has limited time available to make a decision. The significance of the information available will vary with the current situation. That is, users of industrial control systems have to deal at least in part with a context sensitivity problem, as in some contexts certain information will be essential and in others irrelevant.
U.S. Pat. No. 6,542,796 entitled Methods and apparatus for integrating, organizing, and accessing flight planning and other data on multifunction cockpit displays, to Gibbs, assigned to Honeywell International Inc. describes methods for integrating, organizing, and accessing flight planning and other data on cockpit displays in aircraft. Different parts of a flight plan and/or information about different functions may be displayed in a series of windows each accessed by a selecting a known graphic display feature in computer systems called a tab.
In U.S. Pat. No. 6,002,398 entitled Navigation between property pages with tabs and menus, assigned to Novell, Inc., a method is described for displaying a tabbed dialog box, a property sheet, which has at least one child window. The parent window or property sheet has a multiple associated, displayable child windows. However at run time the described program loads all of the objects, including graphics, for all the child windows after user initiates the action which represents a heavy load on processor, display and system resources at runtime.
WO01/02953 describes a method for integration of many and various types of applications in a computerized system. This method is based on a concept where real world objects are represented as composite. Different facets of a real world object, such as its physical location, the current stage in a process, a control function, an operator interaction etc., are described as different aspects of the composite object. In this application, composite objects as defined by WO01/02953 are referred to as aspect objects.
A feature of the method described in WO01/02953 is that aspect objects can be organized in structures. A structure of aspect objects is a hierarchy of object instances. It may be based on any type of relations between aspect object instances. An aspect object can be placed in several structures at the same time, where the different structures represent different relations, e.g. functional and physical containment (functional structure and location structure).
A further application of the method of WO01/02953 is described in US-2002-0046290-A1. A meta object representing an entity is typically represented in several hierarchical structures at the same time within a control system. For example, a certain piece of process equipment has a certain position in a functional structure depending on the functional breakdown of the plant. It has also a physical position, and thus it has a place in a location structure. The same piece of equipment may currently be allocated to a certain production order, so it belongs to an order structure. Because it is used to produce a certain product, it also fits in a product structure.
Finding the right information in control systems is often difficult because the information space is so large. There are often 10s of thousands of individual tag names and hundreds or thousands of process graphics, so that the task of navigation between control interfaces for different parts of processes is often difficult or time consuming. The most common navigation method is to have links arranged with or around the process graphics. The navigation methods are otherwise limited to back/forward and history, context menu, display shortcut buttons and the like. Although different navigation schemes have been proposed they often demand considerable additional engineering or considerable system resources, or both.
Operators and system engineers need to navigate as quickly as possible within the different objects, aspect and or windows of the process control workplace. Navigating wrongly and having poor ways of managing the windows or objects which means under normal operation increased operator fatigue, and can mean during unexpected events that seconds are lost and can potentially be the cause of a plant shutdown or an accident. For a system engineer, poor navigation systems can force him/her to adopt a non-optimal or non desirable workflow for engineering the system, causing both errors and increased engineering time.